Portfolio groups - ungrouped holdings

’ Portfolio Groups’ allows us to group holdings from different portfolios. We can assign holdings to different categories (manage groups - add category) and we can have list of those categories in ‘group portfolio’ view. However holdings which are not assigned to any category will be listed in ‘group portfolio’ as ‘ungrouped’.
I really would like to have a feature where we can say do not show (calculate) in this ‘group portfolio’ holdings which are not assigned to any category.
Why is this feature important. Let’s say you have holdings in different brokers (like CommSec, Stake etc) and your portfolios are exact copy of those brokers. Now you want to have a group of particular stock category (IT, finances etc) and you want to check performance of those categories but not any other holdings. In this case we could create new ‘portfolio group’ and add particular categories but exclude all other stock we do not want to track.
This feature would be very useful and from technical point of view should be easy to do.